the given tableau represents a solution to a linear programming problem that satisfies the optimality criterion but is infeasible. Use the dual simplex method to restore feasibility.

$|||5|6|0|0|0|0||$

$|---|---|---|---|---|---|---|---|---|$

$|$ cb $||$ x$1|$ x$2|$ x$3|$ x$4|$ x$5|$ x$6|$ cb $|$

$|5|$ x$1|1|0|0|-1|1|0|4|$

$|6|$ x$2|0|1|0|1|-2/3|0|10/3|$

$|0|$ x$3|0|0|1|7|-8|0|2|$

$|0|$ x$6|0|0|0|0|-1/3|1|-1/3|$

$|||0|0|0|1|1|0|40|$